1. Field of the Invention
The present invention generally relates to a small printer used with, for example, an electronic cash register of a POS (Point Of Sale) system, and more particularly, to techniques of enabling the -printer to easily and quickly clearing a paper jam occurred in a separate type paper cutter mechanism that comprises a printer-body-side part and a movable-cover-side part, which are separated from each other.
2. Description of the Related Art
Generally, the printer of the electronic cash register is configured so that paper is fed out of a roll thereof and then data is printed on the paper on a paper conveying path by a thermal head, and that subsequently, the paper is cut off and discharged as a receipt. In recent years, a printer of the type, in which a cover for opening and closing a paper accommodating portion is rotatably attached to a printer body having a printing mechanism and the paper accommodating portion, has been brought into the mainstream of the printer of the electronic cash register. An example of a paper cutter mechanism provided in the printer of such a type is a separate press-cutting type paper cutter mechanism, in which each of a fixed blade and a movable blade is constituted by a plate-like blade and in which the fixed blade is provided in a cover side and the movable blade is provided in a printer body. This separate type cutter mechanism is such that the fixed blade faces the movable blade across the paper conveying path in a normal state, in which the cover is closed, that the movable blade is caused to perform reciprocating motion between the printer body and the cover, at which the fixed blade is placed, and that both the blades cut the paper in cooperation with each other by superposing the movable blade on the fixed blade when the movable blade moves to the cover. In this case, it is preferable for cutting the paper smoothly that the movable blade is superposed on a downstream side of the paper conveying path with respect to the fixed blade. Furthermore, generally, other press-cutting cutters (for instance, a paper cutter for use in an office) are configured in such a manner.
In the case of the separate type cutter mechanism, the movable blade is provided in the printer body. Thus, naturally, a drive mechanism (such as a motor or a reduction gear) for driving this movable blade is also provided in the printer body. Therefore, such a separate type cutter mechanism is advantageous in preventing occurrences of drawbacks, which would be caused in the case of providing the movable blade in the cover, that is, drawbacks that the weight of the cover is increased, and that wiring becomes complex. Meanwhile, in the cutter mechanism adapted to cut paper by using a plate-like fixed blade and a plate-like movable blade, a paper jam, by which paper is put between the two blades, may occur, and the movable blade may be locked by being simultaneously superposed onto the fixed blade. Although a paper jam can be cleared by opening the cover, the movable blade superposed onto the fixed blade prevents the cover from opening. Thus, the cover cannot be opened. Therefore, to solve a paper jam, the printer is forced to return the movable blade to a home position during the paper is put between both the blades. To that end, a user is forced to perform, for instance, a troublesome operation of manually rotating a pinion of a drive motor for the movable blade and a reduction gear in a direction, in which the movable blade is moved back to the printer body.
The present invention has been made to solve the above problem, and therefore an object of the present invention is to provide a printer which can easily and quickly clear a paper jam occurring in a separate type cutter mechanism.
According to the present invention, there is provided a printer that comprises a printer body, which has a paper accommodating portion, a paper conveying path, and a printing mechanism for printing data on paper conveyed on the paper conveying path, a body cover rotatably and disengageably attached to the printer body in such a manner as to close the paper accommodating portion, and a paper cutter mechanism for cutting paper on the paper conveying path at the downstream side of the printing mechanism. In this printer, the paper cutter mechanism comprises a fixed blade provided in the printer body, a movable blade provided on the body cover so as to face the fixed blade across the paper conveying path when the body cover is closed, and to be able to perform reciprocating motions with respect to the fixed blade, and to cut paper in cooperation with the fixed blade by being superposed on the fixed blade when moved toward the fixed blade, and drive means for causing the movable blade to perform reciprocating motions.
According to the printer of the aforementioned configuration, paper is accommodated in the paper accommodating portion by opening the body cover. Thereafter, when the body cover is closed and engaged with the printer body, the printer is put into a ready state. During the printer is working, a fundamental operation is performed as follows. That is, the paper accommodated in the paper accommodating portion is conveyed on the paper conveying path. Halfway through the conveyance, the printing mechanism prints data on the paper. Upon completion of printing, the movable blade moves toward the fixed blade side. Then, the printing paper is cut by using both the blades. Upon completion of cutting, the movable blade is moved back and returned to the initial position thereof.
Meanwhile, according to the present invention, in the case that a paper jam, by which the paper is put between both the blades, occurs when the paper is cut (or when the movable blade moves toward or back from the fixed blade), the paper jam can be cleared by opening the body cover having the movable blade. That is, the movable blade is superposed on the fixed blade when moved toward the fixed blade. This prevents the movable blade from abutting against the fixed blade when the body cover is opened, and from hindering an opening operation of the body cover. Consequently, a paper jam clearing operation can quickly be performed by opening the body cover and removing a jammed part of the paper.
Further, the paper having passed through the paper cutter mechanism is not under tension but is in a free state. In contrast, the paper placed on the upstream portion of the paper cutter mechanism is under tension caused by the printing mechanism or the subsequent portion of the paper. Incidentally, the paper is fixed under tension at the fixed blade side by superposing the movable blade at the downstream of the fixed blade. Conversely, the paper is in a free state at the movable blade side. Thus, the paper is cut well. Consequently, there is no fear that a cut sheet is damaged. In contrast with this, in the case of employing the configuration in which the movable blade is superposed at the upstream of the fixed blade, the paper held under tension may interfere with the movable blade. Further, the paper on a fixed-blade side portion of the path may be insecurely fixed thereto. Thus, the movement of the movable blade may cause the fixed-blade-side paper to move. Consequently, the cutter mechanism employing this configuration is relatively inferior in the degree how well is cuts the paper. Moreover, the movable blade may damage and streak the paper.
Furthermore, preferably, an embodiment of the printer according to the present invention, a fixe-blade cover is provided in the printer body in such a manner as to face the rotating end portion of the body cover, which is in a closed state, and to cover the fixed blade when the body cover is in an opened state. This embodiment prevents the fixed blade from being touched in a state in which the body cover is opened. This is an effective safety measure, especially, when the paper is accommodated in the paper accommodating portion. Moreover, in this embodiment, preferably, this fixed-blade cover does not interfere with the body cover when the body cover is engaged with or disengaged therefrom. To that end, it is sufficient that the fixed blade is enabled to retreat from the rotating end portion of the body cover in such a way as to allow an disengaging motion of the body cover with respect to the printer body.
Additionally, preferably, an embodiment of the printer of the present invention includes a locking mechanism for locking the fixed-blade cover at a position, at which the fixed-blade cover covers the fixed blade, and at a predetermined position that is opposite to the rotating end portion of the body cover. Consequently, even in the case that the fixed-blade cover is touched when the body cover is opened, the fixed-blade cover does not move. Thus, safety is ensured. On the other hand, in the case that the printer is in an operational state in which the body cover is closed, the immobile state of the fixed-blade cover is maintained.
Further, preferably, an embodiment of the printer of the present invention includes cover opening means for enabling the body cover to open by canceling an engaged state, in which the body cover engages with the printer body, is provided in the printer body. Moreover, the printer is adapted so that when the cover opening means is operated, the fixed blade operates together therewith and retreats from the rotating end portion of the body cover. According to this embodiment, when the cover opening means is operated, the fixed blade operates together therewith and retreats from the rotating end portion of the body cover. Furthermore, the engaged state, in which the body cover engages with the printer body, of the body cover is canceled. Thus, the body cover can smoothly be opened by a single operation. Preferably, the cover opening means is, for instance, a lever to be pushed in a direction, in which the fixed-blade cover retreats.